http://europepmc.org/abstract/MED/15257941
http://europepmc.org/abstract/MED/23926297
http://europepmc.org/abstract/MED/27029036
http://europepmc.org/abstract/MED/24850867
http://europepmc.org/abstract/MED/24030381
http://europepmc.org/abstract/MED/23831921